| 摘要 |
<p>A hydraulic power steering system in which hydraulic pressure for generating steering assistance power is varied by varying the opening of a variable throttle section through movement of a spool. A spool is arranged at a temporary origin by driving a stepping motor in one direction from the position at the time of starting control according to the number of steps for setting a temporary origin and then the number of steps at the time of completing the driving is set at the temporary origin for operation. Under a state for allowing reset to origin where the spool is arranged at the temporary origin and the number of steps from the temporary origin for operation is zero, the number of steps at the time of completing driving of the stepping motor determined by subtracting the number of steps for setting the temporary origin from the number of steps for setting the origin is set at the origin for operation thus blocking movement of the spool at the origin by means of a stopper. After setting the origin for operation, the number of steps from the origin for operation is set in place of the temporary origin for operation depending on the operating conditions of the vehicle for determining the position of the spool.</p> |
